Shafts such as automotive camshafts which are preground in earlier stages of the process, can be subjected to a prefinish grinding or polishing and a fine-finish grinding or polishing in an apparatus wherein two sets of grinding or polishing tools are used, between ends of a pair of levers, at which the tools can be provided and which can be pressed against the workpiece.
For that purpose, the levers are provided with respective actuators, e.g. fluid-operated piston-and-cylinder assemblies which, under the control of a programming unit, can be operated to urge the tools toward and away from the axis of the workpiece.
An earlier machine of this type is described in German Patent DE 38 41 976, commonly owned with this application.
In that apparatus, the two sets of tools for one and the other stage of the machining operation are brought into play by vertically displacing the lever assembly, i.e. raising and lowering the lever assembly.
While that system has been found to be highly effective for two-stage machining, it is insufficiently versatile to accommodate all of the possibly different grinding and polishing requirements.
For example, the grinding stones cannot be simply and easily interchanged or replaced, thereby posing a handicap when an automated system is desired. It is also not possible with that earlier system to conventionally substitute grinding or polishing tools utilizing, for example, a continuous grinding belt.